There is some evidence to suggest that inoperable gliomas may respond to the direct intra-arterial infusion of certain chemotherapeutic agents. Agents currently used have a significant ophthalmic toxicity when infused directly into the internal carotid artery. Selective perfusion of the chemotherapeutic agent beyond the carotid siphon would be preferable, but it is difficult to maneuver conventional catheters into this location, and spasm of the carotid artery induced by such large catheters is a significant hazard. We have been developing two microcatheters based upon the toposcopic principle and a retrograde pulsion principle for traversing tortuous vascular beds. Both catheters are undergoing extensive testing in animals and an IDE application from the FDA has been applied for in the cases of toposcopic catheter. When approved, both catheters will be selectively introduced through a conventional angiographic catheter, negotiated across the carotid siphon and positioned in the distal internal carotid artery or proximal middle cerebral branches for chemotherapeutic perfusion. Significance of Research: The ability to manipulate tortuous vessels with a catheter in order to deposit chemotherapeutic or embolizing agents is a major research area of this department. It would enable more effective localized perfusions of chemotherapeutic agents, not only in the head but in the liver and other organs and also aid in the embolization of complex arteriovenous malformations and tumors.